검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 606

        221.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구의 목적은 고라니(Hydropotes inermis argyropus)의 위내용물을 대상으로 PCR-DGGE 방법을 이용하여 그 식이습성을 조사하는데 있다. 이 연구를 위해, 강원도 철원과 전라남도 동부지역 등에서 자연사 혹은 로드킬에 의해 죽은 고라니 사체의 위에서 식이물 샘플을 채취하였다. 총 44개체의 위내용물에서 각각 DNA를 추출하였고, 두 가지의 프라이머(rbcLZ1과 rbcL19bR)를 이용하여 ribulose-1,5-bisphosphate carboxylase large subunit(rbcL) gene을 PCR 증폭하였다. 44개의 샘플 중 29 샘플에서 성공적으로 PCR을 수행하였다. 이 29개 partial rbcL gene의 PCR product는 PCR-DGGE에 이용되었다. 식이물에 대한 분석결과 총 6과의 식물이 확인되었다. 강원도 철원의 경우, 5과가 나타난 반면, 전라남도 동부의 경우, 3과만이 확인되었다. 이 연구에서는 종수준의 먹이식물의 구별에는 실패하였 지만, 차후 이 PCR-DGGE 기법은 고라니를 포함한 초식동물의 식이습성을 분석하는데 하나의 가능성 있는 방법이 될 것으로 생각된다.
        4,000원
        222.
        2010.06 구독 인증기관 무료, 개인회원 유료
        마이크로파를 열원으로 이용하는 화학반응은 어려운 반응을 활성화시킬 수 있고 반응시간과 속도를 가속화하여 고수득율 및 높은 분자량을 얻는 고분자를 합성하는데 유용하게 쓰일 수 있다. 본 연구에서는마이크로파를 이용하여 Diels-Alder 반응을 실시하고 열적으로 안정한 측사슬계 2차 비선형광학고분자를 합성하였다. 일반적인 수열반응을 통해 얻어진 고분자와 물리적, 열적, 광학적 특성을 비교 분석하였으며 마이크로파 가열을 활성화하기 위해 용매를 달리하고 이온성액제를 첨가하여 반응을 조절하였다. PAMID시리즈의 다양한 고분자를 합성하였으며 이중에서 PAMID-M2는 10분간 120W의 전력을 사용하여 얻어졌으며 이 때 사용한 용매는 이온성액제가 소량 첨가된 trichloroethane을 사용하였다. 얻어진PAMID-M2의 무게평균 분자량은 18,300이었으며 분포도는 1.3이었고 높은 유리전이온도 (123oC)를 나타냈다.
        4,000원
        223.
        2010.05 구독 인증기관·개인회원 무료
        An expression of adult wing form in reaction to rearing density during nymphal stage was investigated in the brown planthopper, Nilaparvata lugens. Under mass rearing condition, the S-BPH and the 2007-BPH population predominantly showed a short-winged, brachypterous, form and a long-winged, macropterous, form, respectively. At rearing density of less than 5 nymphs in the 2007-BPH, 90% of females showed brachypterous form, but all males became macropterous form. The ratio of macropterous form in the 2007-BPH males decreased by 75% in 10 to 15 rearing density, but increased by more than 95% again at 20 to 30 rearing density. In the case of the 2007-BPH females, the ratio of macropterous form gradually grew from 31% at 10 nymphal density to 92% at 20 nymphal density. All females originated from the S-BPH showed brachypterous form, regardless of nymphal density. The ratio of macropterous males in the S-BPH rapidly went down from 74% at 1 nymphal density to 10% at 10 nymphal density. At 20 nymphal rearing density, all males of the S-BPH showed brachypterous form. On the other hand, other brachypterous (OJ67-BPH) and macropterous (2006-BPH) population produced similar results with above the two populations at 1 nymphal rearing density. In summary, these results demonstrate that wing form dimorphism in N. lugens is largely influenced by nymphal density and the wing form at a specific density (low or high) can be different by sex or N. lugens populations.
        224.
        2010.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        고온 용융염 전해환원 공정은 후행핵연료 주기의 대안 공정인 파이로공정의 산화물 사용후핵연료의 확대 를 위해 필수적인 공정이다. 사용후핵연료는 다성분 산화물로 이루어져 있으며 각 산화물은 전해환원 공정 에서 화학적 특성에 따라 산소를 잃게 된다. 본 연구에서는 건식분말화 공정 이후 전해환원 반응기에 도입되 는 사용후핵연료 조성을 기준으로 각 금속-산소 시스템을 독립적인 이상고용체로 가정하여 전해환원 반응거동을 계산하였다. 전해환원을 Li의 환원과 이어지는 Li과의 화학반응의 결합으로 산정하여 U을 비롯한 금 속 환원 거동을 계산하였다. 계산결과 대부분의 산화물들은 전해환원 공정에 의해 금속으로 전환되는 것으 로 예상되었다. 란타나이드 원소들의 경우 Li2O의 농도가 낮아지면 금속 전환율이 높아지나 대부분 산화물로 존재하는 것으로 나타났다. 추가적으로 U3O8의 전해환원 거동에 대해 Li의 확산과 Li과의 화학반응을 고려하 여 반실험적 모델이 제시되었다. 실험데이터를 활용하여 매개변수를 결정하였으며 시간에 대한 환원율 및 전류에 대한 99.9% 환원 시간을 계산하였다.
        4,600원
        225.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Esterification reaction between succinic acid and 1,4-butanediol was kinetically investigated in the presence of nontoxic organometallic compound catalyst(ESCAT-100E) at 150-190℃. The reaction rates measured by the amount of distilled water from the reaction vessel. The Esterification reaction was carried out under the first order conditions respect to the concentration of reactants, respectively. The overall reaction order was 2nd. The linear relationship was shown between apparent reaction rate constant and reciprocal absolute temperature. By the Arrhenius plot the activation energy have been calculated as 376.13 kJ/mol under nontoxic organometallic compound catalyst and also apparent reaction rate constant, k' was found to obey first kinetics with respect to the concentration of catalyst.
        4,000원
        226.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        HOMO(the highest occupied molecular orbital) and LUMO(the lowest unoccupied molecular orbital) of four recalcitrant polycyclic aromatic hydrocarbons (PAHs) were calculated by MOPAC program(CaChe Co). The previous papers which reported experimental results about radical reaction of PAHs were reviewed. The reported radical reaction positions of four PAHs corresponded with predicted positions in which δE(HOMO-LUMO) was high. From these results, it appears that determining the δE(HOMO-LUMO) of a PAH is a promising method for predicting the radical reaction position.
        4,000원
        227.
        2010.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        HDDR treated anisotropic Nd-Fe-B powders have been widely used for the sheet motors and the sunroof motors of hybrid or electric vehicles, due to their excellent magnetic properties. Microstructural alignment of HDDR treated powders are mostly depending on the hydrogen reaction in disproportionation step, so the specific method to control hydrogenation reaction is required for improving magnetic properties. In disproportionation step, hydrogenation pressure and reaction time were controlled in the range of 0.15~1.0 atm for 15~180 min in order to control the micorstructural alignment of phase and, at the same time, to improve remanence of HDDR treated magnet powders. In this study, we could obtain a well aligned anisotropic Nd-Fe-B-Ga-Nb alloy powder having high remanence of 12 kG by reducing hydrogen pressure down to 0.3 atm in disproportionation step.
        4,000원
        228.
        2009.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The electrocatalytic characteristics of oxygen reduction reaction of the PtxM(1-x) (M = Co, Cu, Ni) supported on multi-walled carbon nanotubes (MWNTs) have been evaluated in a Polymer Electrolyte Membrane Fuel Cell (PEMFC). The PtxM(1-x)/MWNTs catalysts with a Pt : M atomic ratio of about 3 : 1 were synthesized and applied to the cathode of PEMFC. The crystalline structure and morphology images of the PtxM(1-x) particles were characterized by X-ray diffraction and transmission electron microscopy, respectively. The results showed that the crystalline structure of the Pt alloy particles in Pt/MWNTs and PtxM(1-x)/MWNTs catalysts are seen as FCC, and synthesized PtxM(1-x) crystals have lattice parameters smaller than the pure Pt crystal. According to the electrochemical surface area (ESA) calculated with cyclic voltammetry analysis, Pt0.77Co0.23/MWNTs catalyst has higher ESA than the other catalysts. The evaluation of a unit cell test using Pt/MWNTs or PtxM(1-x)/MWNTs as the cathode catalysts demonstrated higher cell performance than did a commercial Pt/C catalyst. Among the MWNTs-supported Pt and PtxM(1-x) (M = Co, Cu, Ni) catalysts, the Pt0.77Co0.23/MWNTs shows the highest performance with the cathode catalyst of PEMFC because they had the largest ESA.
        4,000원
        229.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Esterification reaction between succinic acid[SA] and 1,4-butanediol [BD was kinetically investigated in the presence of organic metal catalysts (alkyl-silver oxide(ASO),CAT 100E) at 150~190℃. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order kinetics with respect to the concentration of reactants and catalyst, respectively. The overall reaction order was 2nd. From the examination of relationship between apparent reaction rate constants and reciprocal absolute temperature, the activation energy has been calculate as 146.70 kJ/mol with ASO catalyst and 43.04 kJ/mol with CAT 100E catalyst.
        4,000원
        232.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Esterification reaction between succinic acid and 1,4-butanediol was kinetically investigated in the presence of monobutyl tinoxide catalysts at 150~190℃. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order conditions with respect to the concentration of reactants, respectively. The overall reaction order was 2nd. The linear relationship was shown between apparent reaction rate constant and reciprocal absolute temperature. By the Arrhenius plot the activation energy have been calculated as 87.567 kJ/mol under monobutyl tinoxide catalyst and also apparent reaction rate constant, k' was found to obey first kinetics with respect to the concentration of catalyst.
        4,000원
        233.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The combustion reaction of polyvinylchloride(PVC) was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to 50℃/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The combustion reaction of PVC proceeded in two steps; the first step was caused by the dehydrochlorination process in PVC, and the second step by the combustion of polyene. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.
        4,000원
        234.
        2009.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To study the behavioral reaction of common squid Todarodes pacificus, to different colors of LED light, individual distribution in the dark condition without LED light stimuli, individual distribution when four colors of light stimuli were at the sections of end and middle of water tank and the changes of gathering rates as the elapse of illuminating time were examined. When it was dark, the distribution of the fish in each section of the tank was U-shape regardless of the investigating time intervals, which means that Todarodes pacificus gathered at the both ends of the tank. The individual distribution when light stimuli were at the one end of the tank showed the tendency of gathering at the illuminated section and decreasing at the opposite section. There were 448 of them at the end of the tank when the light was blue, 352 when white, 302 when green and 132 when red. Thus the fish liked blue light the most, followed by white light. The variations of gathering rate at the both ends of tank as illuminating time elapsed showed the tendency of increasing at the light section (A section), however, it showed the tendency of decreasing at the darkest section (F section). The individual distribution showed the tendency of letter Λ of gathering at the center and decreasing at the both ends mostly when the light stimuli were at the middle section of tank. The gathering rates at the lighting section were 80.4% when red, 76.4% when white, 69.6% when green and 56.7% when blue. The fishes showed the affinity for the red light mostly, followed by the white light source. The red light and blue light showed the opposite when the light stimuli were at the one end of water tank. The variations of gathering rates as the elapse of time at the lighted section showed the tendency of gradual increasing in the four light sources. The color of light source showing the highest gathering rate within 25-30 minutes of light stimuli was the white, followed by the red.
        4,000원
        235.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 음지에서 잘 자라는 자생 지피식물 선발을 위해 7종의 자생식물을 대상으로 광 조건을 달리하여 생장반응을 조사하였다. 비비추는 자연광의 60% 차광에서 가장 좋은 생장을 보였으며, 맥문동은 90% 차광에서 생육이 매우 좋았다. 관중은 60% 차광에서 생육이 가장 우수 하였으며, 대사초는 40% 차광에서 초장과 초폭이 신장이 좋았고 엽수도 많았다. 비비추, 맥문동, 관중 및 수호초는 차 광율이 높을수록 엽록소 함량이 점차 증가되었으며, 맥 문동은 완전음지나 자연광에서는 개화되지 않았다.
        4,000원
        237.
        2009.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In chemistry, the study of sonochemistry is concerned with understanding the effect of sonic waves and wave properties on chemical systems. In the area of chemical kinetics, it has been observed that ultrasound can greatly enhance chemical reactivity in a number of systems by as much as a million-fold. Nano-technology is a super microscopic technology in which structures of 100 nanometers or smaller can be investigated. This technology has been used to develop TiO2 materials and TiO2 devices of that size. Thus far, electrochemistry methods and photochemistry methods have generally been used to create TiO2 nano-size particles. However, these methods are complicated and create pollutants as a by-product. In the present study, nano-scale silver particles (5 nm) were prepared in a sonochemistry method. Sonochemistry deals with mechanical energy that is provided by the collapse of cavitation bubbles that form in solutions during exposure to ultrasound. TiO2 powders 25 nm in size doped with Ag were formed using an ultrasonic sound technique. The experimental results showed the high possibility of removing pollution through the action of a photocatalyst. This powder synthesis technique can be considered as an environmentally friendly powder-forming processing owing to its energy saving characteristics.
        4,000원
        238.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research aimed to compare the detection methods of Anisakis simplex in Sea fish by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and macroscopic inspection. We examined 18 Trichiurus lepturus, 11 Scomber japonicus, and 65 Todarodes pacificus collected from the retail markets in the areas of Uljin, Kyuonggi province and Seoul. As the result of examinations, we found that detection rate of Anisakis simplex by macroscopic observation was 89% in Trichiurus lepturus, 90.9% in Scomber japonicus, 32.3% in Todarodes pacificus. The detection rate of Anisakis simplex by PCR-RFLP was 77.7% in Trichiurus lepturus, 81.8% in Scomber japonicus, 26.1% in Todarodes pacificus. We could conclude that PCR-RFLP method of Anisakis simplex was more specific rather than macroscopic observation.
        4,000원
        239.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to observe the histopathologic reaction in vital bone to various surface treated implants. For this purpose, ten New Zealand Albino rabbits, weighing 3.3 to 4kg were used as experimental animals. All the experimental groups divided into five groups; 1) Machined surface as control, 2) RBM(resorbable blast media), 3) RBM etched nitric acid solution, 4) RBM etched sodium hydroxide solution, 5) RBM etched acid, alkali, and heat treated group on each. All the surfaces of implants were examined under the scannning electron microscope to distinguish the differences between each experimental groups compare to that on the control group. All the rabbits were implanted into the tibial metaphyses of rabbits. On the 4th and 8th week after implantations, all the experimental rabbits were sacrificed. All the tissues containing each implanted materials were fixed in ethyl alcohol, and embedded in spurr resin as usual manner, sectioned in 10μm or more thickness, grinded, stained with the Villanuevaʼs osteochrome bone stain method and examined histopatholgically. For the fluorescence microscopic examination, three kind of fluorescence dyes, Oxytetracycline, Alizarin-Complexone, and Xylenol-Orange were injected to put into the bone to implant interface produced polychromatic fluorescence labelling on the 1st week, 2nd week, and 5th week on each. On the 8th week after experiments, the animals sacrificed, and the tissues containing the implants were taken, fixed in ethyl alcohol and embedded in spurr resin, sectioned, grounded 10um in thickness and examined under the fluorescence microscope. Following results were obtained; On the scanning electron microscopic examination of the implants, dull cracks, continuous linear indentations were revealed on the machined surface implant, irregular multiple leaflike eruptions on the RBM, and more sharp porous indentation with multiple complicated c rack s on the RBM acid etched surface, and more dull margins on complicated porous indentation on the RBM alkalic etched surface and more dull and less indented particles were noted on the RBM, acid, alkalic etched, heat treated surface, On the histopathologic examination, on the 4th week after experiment, complete osseointegation was noted between the implant and cortical bone on the collar and the apex lesion. and in parts, small newly formed bone spicules directly attached to the screws, and osteoid tissues were revealed in marrow tissues, in all experimental groups. On the histopathologic examination, on the 8th week after experiment, osseointegration is more increased compare to that on the 4th week group, the amount of bone trabeculae and osteoid tissues directly fused to screw of implants were markedly increased. On fluorescence examination, band or linear shape was witnessed on the boarder of compact bone and marrow tissues, and on bone trabeculae according to the formed age. and precipitated as granular and globular shape on the haversian canals. These results indicate that the surface treated method used for the present study render the implants compatible to bone tissue but the tissue compartibility is not different among the surface treated implants.
        4,600원
        240.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The combustion reaction of polypropylene was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to 50℃/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Freeman-Carroll, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.
        4,000원